Algebra Play — Class 8 MCQs with Answers
Class 8 CBSE Mathematics · Chapter 13
72 practice questions · 24 Easy · 24 Medium · 24 Hard · Updated
Practise the most important Class 8 CBSE Mathematics questions from Chapter 13, "Algebra Play". You get 9 timed quizzes made from 72 NCERT-based MCQs, with answers and explanations. The questions are split into 24 Easy, 24 Medium and 24 Hard. Warm up on the basics, then move on to the exam-level questions that top scorers in CBSE Board exams get right.
To score well in "Algebra Play", focus on fast problem-solving, formula recall and step-by-step working. Each MCQ here is timed and uses exam-style marking (+4 correct, −1 wrong, 0 skipped). This helps you stay accurate when time is short, just as real papers need. Every question has a short explanation, so a wrong answer becomes a quick lesson. It is the fastest way to fix gaps before a test.
Use this chapter for focused revision. Start with the Easy set to check your basics on Algebra Play, then move to Medium and Hard to practise applying them. Your accuracy, streaks and XP save automatically. This chapter also adds to your overall Class 8 Mathematics mastery score. 14 sample questions are solved in full below, with the answer and a worked explanation. Sign in free to start practising.
Algebra Play — important questions & MCQs with answers (Class 8 Mathematics)
14 solved questions from this chapter's difficulty levels, each with its answer and explanation.
- Q1Easy
In algebra, a letter used to stand for an unknown number is called a:
A.variable✓ CorrectB.constantC.sumD.equationAnswer: A. variable
Explanation: A variable is a letter standing for an unknown or changing value; a constant, like 5, is a fixed number and never changes — the two ideas are different.
- Q2Easy
If x = 5, the value of x + 3 is:
A.15B.2C.8✓ CorrectD.53Answer: C. 8
Explanation: Substitute x = 5 into the expression: 5 + 3 = 8. Concatenating the digits instead of adding would wrongly give 53.
- Q3Easy
'5 more than a number x' is written as:
A.5xB.x − 5C.x + 5✓ CorrectD.5 − xAnswer: C. x + 5
Explanation: 'More than' means add: 5 more than x is x + 5. Writing 5 − x reverses the order and gives a different value.
- Q4Easy
If a = 4, the value of 2a is:
A.6B.8✓ CorrectC.24D.16Answer: B. 8
Explanation: 2a means 2 × a, so with a = 4: 2 × 4 = 8. It is not 2 + 4 = 6 — the coefficient multiplies, it does not add.
- Q5Easy
'Twice a number n' is written as:
A.n + 2B.n²C.n − 2D.2n✓ CorrectAnswer: D. 2n
Explanation: 'Twice' means multiply by 2, so twice n is 2n — not n² (n multiplied by itself) and not n + 2 (adding 2 instead).
- Q6Easy
If y = 6, the value of y − 2 is:
A.4✓ CorrectB.8C.3D.12Answer: A. 4
Explanation: Substitute y = 6: 6 − 2 = 4. Adding instead of subtracting would wrongly give 8.
- Q7Medium
A pencil costs ₹x. The cost of 5 pencils is:
A.₹(x + 5)B.₹x/5C.₹5D.₹5x✓ CorrectAnswer: D. ₹5x
Explanation: 5 pencils at ₹x each cost 5 × x = ₹5x. Adding instead of multiplying would wrongly give ₹(x + 5).
- Q8Medium
If x = 3 and y = 2, the value of 2x + 3y is:
A.10B.12✓ CorrectC.13D.5Answer: B. 12
Explanation: Substitute and multiply first: 2 × 3 = 6 and 3 × 2 = 6, then add: 6 + 6 = 12. Adding x and y before multiplying would give a smaller, wrong total.
- Q9Medium
Solve x + 5 = 12.
A.17B.5C.7✓ CorrectD.60Answer: C. 7
Explanation: To isolate x, subtract 5 from both sides: x = 12 − 5 = 7. Adding 5 instead would wrongly give 17.
- Q10Medium
Think of a number, double it, add 6, halve the result, then subtract the original number. You always get:
A.3✓ CorrectB.6C.the original numberD.0Answer: A. 3
Explanation: (2n + 6)/2 − n = (n + 3) − n = 3 for every n — the n cancels out, so the result is always the constant 3, not the original number.
- Q11Medium
Ravi is x years old now. His age after 4 years will be:
A.4xB.x − 4C.4D.x + 4✓ CorrectAnswer: D. x + 4
Explanation: After 4 more years his age increases by 4, giving x + 4, not 4x, which would multiply his age instead of adding to it.
- Q12Hard
Solve 3x − 7 = 2x + 5.
A.−2B.2C.12✓ CorrectD.4Answer: C. 12
Explanation: Move x-terms together: 3x − 2x = x, and 5 + 7 = 12, so x = 12. Subtracting 3x from 2x instead (reversing the terms) would wrongly give a negative value like −2.
- Q13Hard
Think of a number, triple it, add 9, divide by 3, then subtract the original. You always get:
A.9B.the numberC.3✓ CorrectD.0Answer: C. 3
Explanation: (3n + 9)/3 − n = (n + 3) − n = 3 for every n — the n cancels, leaving the constant 3, not the original number.
- Q14Hard
Solve 5x + 4 = 3x + 14.
A.9B.4.5C.5✓ CorrectD.2Answer: C. 5
Explanation: Move x-terms: 5x − 3x = 2x; move constants, subtracting: 14 − 4 = 10, so x = 5. Adding instead of subtracting the constants (14 + 4 = 18) would wrongly give x = 9.
Key concepts: Algebra Play (Class 8 Mathematics)
This chapter plays with algebra to explain and invent number tricks. A variable is a letter that stands for any number, and expressions are built from variables, coefficients and constants. You simplify expressions by combining like terms, evaluate them by substituting values, and solve simple equations by doing the same operation to both sides. The real fun is generalising — using a letter to prove why a 'think of a number' trick, a number pyramid or a digit-reversal always works.
- Variable
- A letter such as x or n that stands for an unknown or changing number, letting us write general rules instead of one-off calculations.
- Expression, term, coefficient
- An expression like 3x + 4 is built from terms (3x and 4); in 3x, 3 is the coefficient and x the variable, while 4 is a constant.
- Like and unlike terms
- Like terms have exactly the same variables (3x and 5x) and can be combined; unlike terms (2a and 3b) cannot be added together.
- Simplifying expressions
- Combine like terms by adding or subtracting their coefficients: 8x + 3 − 3x + 2 becomes 5x + 5.
- Substitution
- Evaluate an expression by replacing each letter with its value and following the order of operations: if x = 4, then 3x − 5 = 7.
- Equation
- A statement that two expressions are equal, such as 2x + 3 = 11; solving it means finding the value of the variable that makes it true.
- Solving an equation
- Keep the equation balanced by doing the same operation to both sides, undoing the operations around the variable until it stands alone.
- Forming expressions from words
- Translate a situation into algebra: '5 more than x' is x + 5, the cost of 5 pencils at ₹x is 5x, and the next number after n is n + 1.
- Explaining tricks with algebra
- A 'think of a number' trick is an expression in n that simplifies to a fixed result, which proves the trick always works, e.g. (2n + 6)/2 − n = 3.
- Generalising patterns
- Letters capture patterns in pyramids and grids; a number pyramid on a, b, c has top block a + 2b + c.
- Digit form of a number
- A two-digit number with digits a and b is 10a + b, which explains why a number plus its reverse is 11(a + b) and the difference is 9(a − b).
Start this chapter free
You have 14 solved above. Sign in with Google (no card needed). You get 1 Easy + 1 Medium quiz on every chapter during your 30-day trial. After that, you keep 1 Easy quiz on every chapter, free for good, plus the formulas & exam tips.
This chapter has 72 questions (24 Easy · 24 Medium · 24 Hard), with timed scoring and instant feedback. The rest unlock with the ₹999/year plan.
Start this chapter free →Algebra Play — FAQs
What are the key concepts in Class 8 Mathematics Algebra Play?+
This chapter plays with algebra to explain and invent number tricks. A variable is a letter that stands for any number, and expressions are built from variables, coefficients and constants. You simplify expressions by combining like terms, evaluate them by substituting values, and solve simple equations by doing the same operation to both sides. The real fun is generalising — using a letter to prove why a 'think of a number' trick, a number pyramid or a digit-reversal always works. Key ideas include Variable, Expression, term, coefficient, Like and unlike terms, Simplifying expressions, Substitution, Equation.
What does Class 8 Mathematics Chapter 13 (Algebra Play) cover on XamBaaz?+
It has 72 NCERT-based MCQs on "Algebra Play": 24 Easy, 24 Medium and 24 Hard. Together they make 9 timed quizzes, and you never get the same set twice. Every question has an instant explanation. They help you prepare for CBSE Board exams.
Are these "Algebra Play" questions free to practise?+
Yes. Sign in with Google to practise "Algebra Play" free. Full unlimited access is ₹999/year. One year from the day you pay. You stay in Class 8 till 31 March; on 1 April your account moves up to Class 9 and the rest of your year carries over. No chapter is charged separately.
How should I revise "Algebra Play" for the exam?+
Start with the Easy quiz to check your basics, then try Medium and Hard to practise applying them. There are 9 timed quizzes on this chapter, so you can come back for a fresh set instead of one you have seen. Read each explanation, retry the questions you miss, and track your accuracy until it stays high.
Are these "Algebra Play" MCQs available with answers?+
Yes. 14 sample questions are shown here in full, each with the correct option and a step-by-step "Why" explanation. Sign in free with Google to start practising, with instant scoring.
Is there negative marking in the "Algebra Play" quizzes?+
Yes. The timed quizzes use exam-style marking: +4 for a right answer, −1 for a wrong one and 0 for a skip. MHT-CET and CBSE board papers have no negative marking. Our mocks for those are scored their way.
What are the important questions from Algebra Play (Class 8 Mathematics)?+
The questions that matter most test Variable, Expression, term, coefficient, Like and unlike terms, Simplifying expressions, Substitution, Equation. This page shows 14 solved important MCQs with answers and explanations. Sign in to practise all 72 questions on the chapter as timed quizzes.
Is there an online quiz for Algebra Play?+
Yes — Class 8 Mathematics Algebra Play has timed online quizzes at Easy, Medium and Hard levels, with instant scoring and a worked explanation on every question. The first quiz on the chapter is free.